Stretchable electronic device

ABSTRACT

A stretchable electronic device includes a substrate, a plurality of electronic elements, and a conductive wiring. The electronic elements and the conductive wiring are disposed on the substrate, and the conductive wiring is electrically connected to the electronic elements. The conductive wiring is formed by stacking an elastic conductive layer and a non-elastic conductive layer. A fracture strain of the elastic conductive layer is greater than a fracture strain of the non-elastic conductive layer, and the non-elastic conductive layer includes a plurality of first fragments which are separated from one another.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional application of patent application Ser. No.17/170,773, filed on Feb. 8, 2021, now allowed, which claims thepriority of Taiwan patent application serial no. 109128440, filed onAug. 20, 2020. The entirety of each of the above-mentioned patentapplications is hereby incorporated by reference and made a part of thisspecification.

BACKGROUND Technical Field

The disclosure relates to an electronic device, and particularly relatesto a stretchable electronic device.

Description of Related Art

With the advancement of display technologies, the development ofstretchable displays tends to become more and more active, so as toperform a display function on stretchable materials. However, conductivewires inside the stretchable displays are easily broken due to excessiveextension.

SUMMARY

The disclosure provides a stretchable electronic device, which canmitigate an issue of easily broken conductive wires due to excessiveextension.

According to an embodiment of the disclosure, a stretchable electronicdevice includes a substrate, a plurality of electronic elements, and aconductive wiring. The electronic elements and the conductive wiring aredisposed on the substrate, and the conductive wiring is electricallyconnected to the electronic elements. The conductive wiring is formed bystacking an elastic conductive layer and a non-elastic conductive layer.A fracture strain of the elastic conductive layer is greater than afracture strain of the non-elastic conductive layer, and the non-elasticconductive layer includes a plurality of first fragments that areseparated from one another. The elastic conductive layer is a continuouswiring. An orthogonal projection of the elastic conductive layer one thesubstrate overlaps orthogonal projections of a plurality of the firstfragments and a plurality of gaps among the plurality of the firstfragments on the substrate.

In an embodiment of the disclosure, the elastic conductive layer islocated between the substrate and the non-elastic conductive layer.

In an embodiment of the disclosure, the non-elastic conductive layer islocated between the substrate and the elastic conductive layer.

In an embodiment of the disclosure, both the non-elastic conductivelayer and the elastic conductive layer are in contact with thesubstrate, and the elastic conductive layer covers the non-elasticconductive layer.

In an embodiment of the disclosure, the non-elastic conductive layer isin contact with the substrate, and the elastic conductive layer coversthe non-elastic conductive layer.

According to an embodiment of the disclosure, another stretchableelectronic device includes a substrate, a plurality of electronicelements, and a conductive wiring. The electronic elements and theconductive wiring are disposed on the substrate, and the conductivewiring is electrically connected to the electronic elements. Theconductive wiring is formed by stacking an elastic conductive layer, afirst non-elastic conductive layer, and a second non-elastic conductivelayer. A fracture strain of the elastic conductive layer is greater thana fracture strain of the first and second non-elastic conductive layers,and the non-elastic conductive layers include a plurality of firstfragments which are separated from one another. The elastic conductivelayer is located between the first non-elastic conductive layer and thesecond non-elastic conductive layer.

In an embodiment of the disclosure, the fracture strain of the elasticconductive layer is greater than 10%.

In an embodiment of the disclosure, the fracture strain of the first andsecond non-elastic conductive layers is less than 10%.

In an embodiment of disclosure, a material of the elastic conductivelayer is at least one of polyacetylene, polypyrrole, polythiophene,polyaniline, poly(p-phenylene), and poly(p-phenylene vinylene).

In an embodiment of the disclosure, when the substrate is not stretched,the first fragments are in contact.

In an embodiment of the disclosure, when the substrate is not stretched,the first fragments are separated from one another.

In an embodiment of the disclosure, a Young's modulus of the substrateis less than 10 GPa.

In an embodiment of the disclosure, the electronic elements are aplurality of display elements.

In light of the foregoing, in the stretchable electronic device providedin one or more embodiments of the disclosure, the conductive wiringformed by the stacking the elastic conductive layer and the non-elasticconductive layer is not easily broken during extension and contractionand has favorable conductivity.

Several exemplary embodiments accompanied with figures are described indetail below to further describe the disclosure in details.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments of thedisclosure and, together with the description, serve to explain theprinciples of the disclosure.

FIG. 1 is a schematic partial view of a stretchable electronic deviceaccording to an embodiment of the disclosure.

FIG. 2A and FIG. 2B are schematic cross-sectional views illustrating anextension direction of the conductive wiring depicted in FIG. 1 beforeand after being stretched, respectively.

FIG. 3A and FIG. 3B are schematic cross-sectional views illustrating anextension direction of a conductive wiring provided in anotherembodiment before and after the conductive wiring is stretched,respectively, and FIG. 3C is an enlarged view of region A indicated inFIG. 1 .

FIG. 4A and FIG. 4B are schematic cross-sectional views illustrating anextension direction of a conductive wiring provided in still anotherembodiment before and after the conductive wiring is stretched,respectively.

FIG. 5A and FIG. 5B are schematic cross-sectional views illustrating anextension direction of a conductive wiring provided in still anotherembodiment before and after the conductive wiring is stretched,respectively.

FIG. 6A and FIG. 6B are schematic cross-sectional views illustrating anextension direction of a conductive wiring provided in anotherembodiment before and after the conductive wiring is stretched,respectively.

FIG. 7A and FIG. 7B are schematic cross-sectional views illustrating anextension direction of a conductive wiring provided in anotherembodiment before and after the conductive wiring is stretched,respectively.

FIG. 8A to FIG. 8D are schematic cross-sectional views of a conductivewiring perpendicular to an extension direction of the conductive wiringaccording to four embodiments, respectively.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the disclosure, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numbers areused in the drawings and the description to refer to the same or likeparts.

Various embodiments of the disclosure are disclosed in the drawings, andfor the sake of clarity, many of the practical details are set forth inthe following description. However, it should be understood that thesepractical details should not be used to limit the disclosure. In otherwords, these practical details are not necessary in certain embodimentsof the disclosure. In addition, to simplify the drawings, someconventional structures and elements in the drawings will be shown in asimple and schematic manner.

Throughout the specification, the same reference numerals in theaccompanying drawings denote the same or similar elements. In theaccompanying drawings, thicknesses of layers, films, panels, regions andso on are exaggerated for clarity. It should be understood that when anelement such as a layer, film, region, or substrate is referred to asbeing “on” or “connected to” another element, it can be directly on orconnected to the other element, or intervening elements may also bepresent between said element and said another element. In contrast, whenan element is referred to as being “directly on” or “directly connectedto” another element, there are no intervening elements present betweensaid element and said another element. As used herein, the term“connected” may refer to physically connected and/or electricallyconnected. Therefore, intervening elements may be present between twoelements when the two elements are “electrically connected” or “coupled”to each other.

It should be understood that, although the terms “first”, “second”,etc., may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers, and/or sections should not be limited by these terms. Theseterms are used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section.

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting of the disclosure. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. Herein, “or” represents “and/or”. The term “and/or” usedherein includes any or a combination of one or more of the associatedlisted items. It will be further understood that the terms “comprise”,“comprising”, “include” and/or “comprising”, when used herein, specifythe presence of stated features, regions, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, regions, integers, steps,operations, elements, components, and/or groups thereof.

Moreover, relative terms such as “below” or “bottom” and “above” or“top” may serve to describe the relation between one element and anotherelement in the text according to the illustration of the drawings. Itshould also be understood that the relative terms are intended toinclude different orientations of a device in addition to theorientation shown in the drawings. For example, if a device in thedrawings is flipped, an element described as being disposed “below”other elements shall be re-orientated to be “above” other elements.Thus, the exemplary term “below” may cover the orientations of “below”and “above”, depending on a specific orientation of the drawings.Similarly, if a device in a figure is flipped over, the elementoriginally described to be located “below” or “underneath” other elementis oriented to be located “on” the other element. Therefore, theillustrative term “under” or “below” may include orientations of “above”and “under”.

The term “approximately” or “substantially” as used herein is inclusiveof the stated value and means within an acceptable range of deviationfor the particular value as determined by persons of ordinary skill inthe art, considering the measurement in question and the errorassociated with measurement of the particular quantity (i.e., thelimitations of the measurement system). For example, “approximately” maymean within one or more standard deviations, or within, for example,±30%, ±20%, ±15%, ±10%, ±5% of the stated value. Moreover, a relativelyacceptable range of deviation or standard deviation may be chosen forthe term “approximately” or “substantially” as used herein based onoptical properties, etching properties or other properties, instead ofapplying one standard deviation across all the properties.

Unless otherwise defined, all terms (comprising technical and scientificterms) used herein have the same meaning as commonly understood bypersons of ordinary skill in the art. It will be further understood thatterms, such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and the disclosure and will not beinterpreted in an idealized or overly formal sense unless expressly sodefined herein.

FIG. 1 is a schematic partial view of a stretchable electronic deviceaccording to an embodiment of the disclosure. With reference to FIG. 1 ,a stretchable electronic device 100 provided in the embodiment 100includes a substrate 110, a plurality of electronic elements 120, and aconductive wiring 130. The electronic elements 120 and the conductivewiring 130 are disposed on the substrate 110, and the conductive wiring130 is electrically connected to the electronic elements 120.

FIG. 2A and FIG. 2B are schematic cross-sectional views illustrating anextension direction of the conductive wiring depicted in FIG. 1 beforeand after being stretched, respectively. In order to highlight thestretching effect in the following embodiments depicted in the drawings,the variation amount of the stretching action is increased, whichhowever does not represent the actual stretching ratio provided in eachembodiment. With reference to FIG. 2A, the conductive wiring 130 isformed by stacking an elastic conductive layer 132 and a non-elasticconductive layer 134. A fracture strain of the elastic conductive layer132 is greater than a fracture strain of the non-elastic conductivelayer 134. That is, on the same conditions, the non-elastic conductivelayer 134 subject to a tensile stress fractures earlier because theamount of strain reaches the amount of strain at fracture, and theelastic conductive layer 132 fractures later because of its largerfracture strain. The non-elastic conductive layer 134 includes aplurality of first fragments 134A separated from one another.Specifically, the first fragments 134A are disconnected from oneanother. However, the first fragments 134A may be in contact with oneanother, as shown in FIG. 2A.

The elastic conductive layer 132 is a continuous wiring. In other words,except for the endpoints of the conductive wiring 130, the conductivewiring 130 is not broken at any other location and is a continuouswiring. An orthogonal projection P12 of the elastic conductive layer 132on the substrate 110 overlaps orthogonal projections P14 of all or aplurality of the first fragments 134A on the substrate 110, and theorthogonal projection P12 of the elastic conductive layer 132 on thesubstrate 110 overlaps orthogonal projections P16 of plurality of gapsG12 among the first fragments 134A on the substrate 110. In other words,the elastic conductive layer 132 is continuous and thus simultaneouslycorresponds to the first fragments 134A and the gaps G12 among the firstfragments 134A. The orthogonal projections P16 of the gaps G12 on thesubstrate 110 as depicted in FIG. 2A appear to be dots, but theorthogonal projections P16 should be in a linear shape if they areobserved from the top of the substrate 110.

On the other hand, on the route of the conductive wiring 130, theelastic conductive layer 132 along the route of the conductive wiring130 is continuous and remains uninterrupted. Here, the continuation ofthe elastic conductive layer 132 indicates that the elastic conductivelayer 132 remains unbroken in design, which does not rule out thecondition that the elastic conductive layer 132 is broken due to poormanufacturing yield or other unexpected factors. In addition, when theconductive wiring 130 itself is divided into a plurality of fragments,the elastic conductive layer 132 is also divided into a plurality offragments along with the conductive wiring 130, but the elasticconductive layer 132 remains unbroken on the single route of theconductive wiring 130. In the embodiment, the non-elastic conductivelayer 134 is located between the substrate 110 and the elasticconductive layer 132, which should however not be construed as alimitation in the disclosure.

With reference to FIG. 2B, when the substrate 110 is stretched, thefirst fragments 134A of the non-elastic conductive layer 134 arranged onthe substrate 110 are separated from one another. At the same time, theelastic conductive layer 132 stacked on the non-elastic conductive layer134 is not broken because of its favorable elasticity. Therefore, thetransmission path of electrical signals remains constant as shown by thearrows in FIG. 2B. Through the first fragments 134A, the electricalsignals have low electrical resistance values at connected parts of thenon-elastic conductive layer 134, and the electrical signals atdisconnected parts of the non-elastic conductive layer 134 may becontinuously transmitted through the elastic conductive layer 132.

It can be learned from the above that by stacking the elastic conductivelayer 132 and the pre-disconnected non-elastic conductive layer 134, theconductive wiring 130 provided in the embodiment is not easily broken atthe time of being stretched; meanwhile, the conductive wiring 130 mayconstantly has the low electrical resistance value. Therefore, thereliability and the performance of the stretchable electronic device 100provided in the embodiment are improved.

In addition, since the substrate 110 is stretched, the orthogonalprojections P16 of the gaps G12 on the substrate 110 as shown in FIG. 2Bare stretched into a line and occupy a certain area if the orthogonalprojections P16 are observed from the top of the substrate 110.

With reference to FIG. 1 , the conductive wiring 130 provided in theembodiment appears to be in form of a curve, which may further reducethe possibility of being broken when the conductive wiring 130 isstretched. In addition, the electronic elements 120 provided in theembodiment are a plurality of display elements. For instance, eachelectronic element 120 may be a light-emitting diode (LED) element andis formed on a rigid substrate, so that the electronic elements 120 maybe protected from being damaged when the stretchable electronic device100 is stretched, and the electrical connections among the electronicelements 120 may be kept by the conductive wiring 130. In addition, aYoung's modulus of the substrate 110 provided in the embodiment is lessthan 10 GPa, for instance, which should however not be construed as alimitation in the disclosure.

With reference to FIG. 2B, for instance, the fracture strain of theelastic conductive layer 132 is greater than 10%. In other words, forinstance, when the stretched and elongated portion of the elasticconductive layer 132 becomes longer than 10% of the original length, theelastic conductive layer 132 may be broken. By contrast, the fracturestrain of the non-elastic conductive layer 134 is, for instance, lessthan 10%. That is, for instance, even when the stretched and elongatedportion of the non-elastic conductive layer 134 is less than 10% of theoriginal length, the non-elastic conductive layer 134 may be broken. Amaterial of the elastic conductive layer 132 may be a conductivepolymer, including but not limited to polyacetylene, polypyrrole,polythiophene, polyaniline, poly(p-phenylene), poly(p-phenylenevinylene), or a combination thereof. Alternatively, the elasticconductive layer 132 may include a polymer material and conductiveparticles mixed therein, and the conductive particles include, forinstance, silver nanowires or carbon nanotubes. A material of thenon-elastic conductive layer 134 is, for instance, selected from thegroup consisting of titanium, aluminum, molybdenum, copper, silver, andindium tin oxide.

FIG. 3A and FIG. 3B are schematic cross-sectional views illustrating anextension direction of a conductive wiring provided in anotherembodiment before and after the conductive wiring is stretched,respectively. The embodiment depicted in FIG. 3A and FIG. 3B is similarto the embodiment depicted in FIG. 2A and FIG. 2B; therefore, only thedifference therebetween is described hereinafter, while the similaritieswill not be further explained. In this embodiment, the non-elasticconductive layer 234 includes a plurality of first fragments 234A thatare separated from one another. Moreover, when the substrate 110 is notstretched, the first fragments 234A are separated from one another.Therefore, when the substrate 110 is compressed, the entire conductivewiring 230 may also be compressible. Optionally, the gaps G22 among thefirst fragments 234A may be filled with the elastic conductive layer232, which should however not be construed as a limitation in thedisclosure. Thereby, the conductive wiring 230 may have the improvedstretchability.

FIG. 4A and FIG. 4B are schematic cross-sectional views illustrating anextension direction of a conductive wiring provided in still anotherembodiment before and after the conductive wiring is stretched,respectively. The embodiment depicted in FIG. 4A and FIG. 4B is similarto the embodiment depicted in FIG. 2A and FIG. 2B; therefore, only thedifference therebetween is described hereinafter, while the similaritieswill not be further explained. In this embodiment, the elasticconductive layer 132 is located between the substrate 110 and thenon-elastic conductive layer 134. When the substrate 110 is stretched,the elastic conductive layer 132 disposed on the substrate 110 does notbreak because of its favorable elasticity. At the same time, the firstfragments 134A of the non-elastic conductive layer 134 stacked on theelastic conductive layer 132 are separated from one another.

FIG. 5A and FIG. 5B are schematic cross-sectional views illustrating anextension direction of a conductive wiring provided in still anotherembodiment before and after the conductive wiring is stretched,respectively. The embodiment depicted in FIG. 5A and FIG. 5B is similarto the embodiment depicted in FIG. 4A and FIG. 4B; therefore, only thedifference therebetween is described hereinafter, while the similaritieswill not be further explained. In this embodiment, the non-elasticconductive layer 334 includes a plurality of first fragments 334A whichare separated from one another. Moreover, when the substrate 110 is notstretched, the first fragments 334A are separated from one another.Therefore, when the substrate 110 is compressed, the entire conductivewiring 330 may also be compressible.

FIG. 6A and FIG. 6B are schematic cross-sectional views illustrating anextension direction of a conductive wiring provided in anotherembodiment before and after the conductive wiring is stretched,respectively. The embodiment depicted in FIG. 6A and FIG. 6B is similarto the embodiment depicted in FIG. 3A and FIG. 3B; therefore, only thedifference therebetween is described hereinafter, while the similaritieswill not be further explained. In this embodiment, there are a firstnon-elastic conductive layer 534A and a second non-elastic conductivelayer 534B, and one elastic conductive layer 532 is located between thefirst non-elastic conductive layer 534A and the second non-elasticconductive layer 534B. Thereby, the conductive wiring 530 may have theimproved reliability. In addition, the elastic conductive layer 532includes a plurality of fragments which are separated from one another,whereby the amount of the material used by the elastic conductive layer532 may be reduced, thus reducing the cost of the conductive wiring 530.Optionally, the gaps G52 among the fragments of the first non-elasticconductive layer 534A may be filled with the elastic conductive layer532, which should however not be construed as a limitation in thedisclosure. In this embodiment, one part of an upper surface 534A1 ofthe first non-elastic conductive layer 534A located at a lower side isnot covered by the elastic conductive layer 532, and the other part ofthe upper surface 534A1 and a side surface 531A2 of the firstnon-elastic conductive layer 534A are covered by the elastic conductivelayer 532.

FIG. 7A and FIG. 7B are schematic cross-sectional views illustrating anextension direction of a conductive wiring provided in anotherembodiment before and after the conductive wiring is stretched,respectively. The embodiment depicted in FIG. 7A and FIG. 7B is similarto the embodiment depicted in FIG. 3A and FIG. 3B; therefore, only thedifference therebetween is described hereinafter, while the similaritieswill not be further explained. In this embodiment, there are a firstnon-elastic conductive layer 634A and a second non-elastic conductivelayer 634B, and one elastic conductive layer 632 is located between thefirst non-elastic conductive layer 634A and the second non-elasticconductive layer 634B. Thereby, the conductive wiring 630 may have theimproved reliability. In this embodiment, an upper surface 634A1 and aside surface 634A2 of the first non-elastic conductive layer 634Alocated at a lower side are both covered by the elastic conductive layer632.

FIG. 8A to FIG. 8D are schematic cross-sectional views of a conductivewiring perpendicular to an extension direction of the conductive wiringaccording to four embodiments, respectively. With reference to FIG. 8A,in the embodiment, the non-elastic conductive layer 834A is locatedbetween the substrate 110 and the elastic conductive layer 832A, andonly the non-elastic conductive layer 834A is in contact with thesubstrate 110. With reference to FIG. 8B, in the embodiment, the elasticconductive layer 832B is located between the substrate 110 and thenon-elastic conductive layer 834B, and only the elastic conductive layer832B is in contact with the substrate 110. With reference to FIG. 8C, inthe embodiment, the elastic conductive layer 832C covers the non-elasticconductive layer 834C, and both the elastic conductive layer 832C andthe non-elastic conductive layer 834C are in contact with the substrate110. With reference to FIG. 8D, in the embodiment, the elasticconductive layer 832D covers the non-elastic conductive layer 834D, andonly the elastic conductive layer 832D is in contact with the substrate110. The above serves as an example of illustrating the cross-section ofthe conductive wiring perpendicular to the extension direction of theconductive wiring according to several embodiments of the disclosure,which should however not be construed as a limitation in the disclosure.

To sum up, in the stretchable electronic device provided in one or moreembodiments of the disclosure, the conductive wiring is not easilybroken, which is one of the characteristics of the elastic conductivelayer, and has the low resistance value, which is one of thecharacteristics of the non-elastic conductive layer. As such, theperformance and the reliability of the stretchable electronic device maybe improved.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed embodimentwithout departing from the scope or spirit of the disclosure. In view ofthe foregoing, it is intended that the disclosure covers modificationsand variations provided that they fall within the scope of the followingclaims and their equivalents.

What is claimed is:
 1. A stretchable electronic device, comprising: asubstrate; a plurality of electronic elements, disposed on thesubstrate; and a conductive wiring, disposed on the substrate andelectrically connected to the electronic elements, wherein theconductive wiring is formed by stacking an elastic conductive layer, afirst non-elastic conductive layer, and a second non-elastic conductivelayer, a fracture strain of the elastic conductive layer is greater thana fracture strain of the non-elastic conductive layers, the non-elasticconductive layers comprise a plurality of first fragments separated fromone another, and the elastic conductive layer is located between thefirst non-elastic conductive layer and the second non-elastic conductivelayer.
 2. The stretchable electronic device according to claim 1,wherein the fracture strain of the elastic conductive layer is greaterthan 10%.
 3. The stretchable electronic device according to claim 1,wherein the fracture strain of the first non-elastic conductive layerand the second non-elastic conductive layer is less than 10%.
 4. Thestretchable electronic device according to claim 1, wherein a materialof the elastic conductive layer comprises at least one of polyacetylene,polypyrrole, polythiophene, polyaniline, poly(p-phenylene), andpoly(p-phenylene vinylene).
 5. The stretchable electronic deviceaccording to claim 1, wherein when the substrate is not stretched, thefirst fragments are in contact.
 6. The stretchable electronic deviceaccording to claim 1, wherein when the substrate is not stretched, thefirst fragments are separated from one another.
 7. The stretchableelectronic device according to claim 1, wherein a Young's modulus of thesubstrate is less than 10 GPa.
 8. The stretchable electronic deviceaccording to claim 1, wherein the electronic elements are a plurality ofdisplay elements.